Electric fuse



F: E. FETRBWGSQ ELECTREC FUSE.

APPLICATION FILED NOV. 18, 191s.

1337,94 Pammra Apr. 20, 1920.

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J. PETROVIGS, OF CHICAGO, ILLINOIS.

ELECTRIC FUSE.

was.

To (all 'ufi/zom it may comm-12 of such a'casing as will admit of theuse of a simple form of fuse, and, whileinexpensive, will be durable anddependable. In this particular instance I have preferred to illustrateand describe what is ordinarily called a cartridge fuse,but it is to beunderstood that the invention may be applied to other forms of fuseblocks or casings.

Of, the accompanying if a wings Figure 1 is a plan view of a fusecartridge embodying the features of my invention. 7 longitudinal sectionof the cartridge fuse Fig. 2 is a along the line 2-2 of Fig. 1. Fig. 3is a transverse section of the cartridge fuse along the line 3-3 of Fig.2. Fig. l is a transverse section along the line i-l of Fig. 2. Fig. 5is a plan view of one of the elements of the cartridge. Fig. 6 is alongitudinal sectional View of a modification of the cartridge.

The fuse cartridge illustrated in Figs. 1 to 5 comprises a casing 10 ofany suitable in sulating material; I prefer for the purpose ordinaryvulcanized fiber. The casing in this instance is cylindrical in formwith open ends, and it thus comprises a tube. Caps 11 and 12 arethreaded on to the respective ends of the tube 10; each cap having fixedthereto, if desired an ordinary contact strip 18, and having a boss l lprojecting inwardly from the central portion thereof. When thefusecartridge is assembled an insulation block 15 is positionedwithinthe tube 10. This block may be of any suitable shape, but is ofsufficient length so that when the caps 11 and 12 are screwed in place afuse 16 having its ends 1'? bent substantially at right angles andextending over the ends of the block 15, Fig. 2, the ends 17 would bepressed firmly between the bosses 14 and the ends 20 of the block. Whenthus assembled the electric circuit is completed between the strips 13,by means of the caps 11 and 12 I Specification of Letters Patent.'Pate'nted' Apr, 20, 1920. Application filed November 18,1918. SerialNo. 263,064. I i

with the projecting bosses 14 pressing on the ends 17 of the fuse.

I prefer to shapethe block 15 as shown in the drawings, so as to haveprojections 20 at each end extending a material distance beyond the endsof the tube 10, so'that the block 15 may be grasped with a tool or bythe fingers and easily removed from the cylinder, in case there shouldbe any tendency to bind therein; and also to have a slot 21 ext-endingthe full length of the block, in

which the fuse 17 is placed; the slot being v materially deeper at itscentral portion than at its ends. This slot'not only limits the width ofthe fuses that can be conveniently used, but also prevents thefuse frombeing in contact with the plug near the central portion thereof, andthus prevents conduction of heat from the fuse and also any tendencyoft-he metal to form a continuous circuit after it has melted.

Although I have specified that the caps 11 and 12 are screwed onto therespective cylinder ends, yet it is to be understood that one cap onlyneed be screwed on, the cap on the other end being fastened thereon inany suitable manner.

Fig. 6 shows a modified form of a cartridge fuse, comprising a cylinder25 composed of any suitable insulation material; I prefer glass for thepurpose. A cap 26 is threaded onto each end of the tube when thecartridge is assembled; with plates 27 positioned between the respectiveends of the cylinder and the caps; the plates having recesses 28therein, and the caps having bosses 29 formed on the inner surfacethereof. When assembled the ends of the fuse 30 are passed through therespective openings 28, turned over across the plates 27 into theopposite openings, and the caps 26 are screwed onto the ends of thecylinder so that the bosses 29 come firmly against the ends of the oneend of said casing, a metallic cap threaded onto the other end of saidcasing, and an insulation block positioned-within said casing andextending substantially from one end to the" other and adapted to holdthe respective ends ofa fuse firmly against the said caps when thethreaded cap is screwed sufficiently onto said cylinder.

2. A refillable fuse case comprising an insulation casing, a metallic'cap mounted on one end of said casing, a metallic cap threaded onto theother'end of said casing, and an insulation block'positioned within saidcasing and extending substantially from one end to the other and adaptedto hold the respective ends of a fuse firmly against the said caps whenthe threaded cap is screwed sufiiciently onto said cylinder.

eachcaphaving a; boss projecting from the inner end wall.

3. A refillable fuse a case comprising an insulation casing, a metalliccap mounted. on

one end of said casing, a metallic cap threaded onto the other end ofsaid casing, and an insulation block positioned within said casing andextending substantially from one end to the other and adapted to holdthe respective ends of a fuse firmly against the said caps when thethreaded cap screwed sufficiently onto said cylinder, said block havinga slot therein adapted to receive a fuse, said slot being deeper at thecentral portion .of said block than at the ends thereof;

a. A refillable fuse case comprising an insulation casing. a metalliccap mounted on one/end of said casing, a metallic cap threaded onto theother end of said casing, and an insulation block positioned within saidcasing and extending substantially from one end to the other end adaptedto hold the respective ends of a fuse firmly against the said cylinder,said block havin a slot therein adapted to receive afuse, said slotbeing deeper at the central portion of said block than at the endsthereof, each cap having a projection extending from its inner endsurface toward the adjacent late.

5. A refillable fuse case comprising an insulation casing, a metalliccap mounted on one end of said casing, a metallic cap threaded onto theother end of said casing, an insulation piece fixed adjacent each end ofsaid casing and facing the cap on said end, each of said caps having aboss projecting inwardly near its central portion, and a fuse extendingthrough said. casing and having its respective ends positioned betweensaid pieces and the adjacent bosses.

In1 testimony whereof, I hereunto set my hanc.

FRED. J. lElROVlC-S.

